The goals of this research are to study the effects of volatile hydro-carbons on the operant behavior of laboratory animals trained on tasks which involve perception and memory. Methods will include a match-to-sample task with juvenile baboons, fixed ratio-fixed interval behavior with rats and a simple discrimination task with rats. Minimal dose levels and exposure times required to produce alterations in behavior will be determined for n-hexane, toluene, trichloroethylene, ketones (methylethyl, methyl butyl), acetone, ethyl acetate, benzene, and freons.